To calculate retainage in construction, add the dollar value of completed work to the value of stored materials, multiply that sum by the retainage percentage in the contract, and subtract the result from the gross amount earned to arrive at the net payment due. Retainage rates on commercial projects typically run between 5% and 10% of each progress payment, and many states cap the rate by statute. The arithmetic is simple; the accuracy depends on pulling the right numbers, applying the right percentage, and tracking the cumulative balance as the job moves forward.
Numbers You Need Before You Calculate
Three figures feed the formula. Pull them from your project records before you open the pay application.
- Gross work completed to date: the dollar value of all labor and installed work through the current billing period, including amounts from previous applications.
- Materials presently stored: the value of materials purchased and delivered to the site or an approved off-site location, but not yet installed.
- Contractual retainage rate: the percentage the owner is required to withhold, found in the payment terms of the prime contract or subcontract.
On projects using AIA Document G702 (Application and Certificate for Payment) with the G703 Continuation Sheet, these figures live in specific columns. Column D shows work completed in previous periods, Column E captures work completed this period, and Column F lists materials presently stored on site. Column G totals the three for each line item. Confusing the current-period column with the cumulative column throws every downstream number off, so read them separately.
The Formula With a Worked Example
Two steps get you the withholding, and a third gets you the check.
A contractor submits a progress billing showing $100,000 in completed work and $20,000 in stored materials. The contract calls for 10% retainage.
- Step 1: $100,000 + $20,000 = $120,000 total earned.
- Step 2: $120,000 × 10% = $12,000 retainage withheld.
- Step 3: $120,000 − $12,000 = $108,000 net payment due.
The $12,000 stays with the owner until release conditions are met. Every subsequent billing repeats the pattern: calculate the cumulative retainage owed to date, subtract retainage already held from earlier draws, and the difference is the new retainage deducted from the current payment.
Filling In Line 5 on the G702
Retainage lives on Line 5 of the G702, split into two sub-lines. Line 5a covers retainage on completed work: take the sum of Columns D and E on the G703 and multiply by the retainage percentage. Line 5b covers retainage on stored materials: multiply Column F by its own retainage percentage. Add 5a and 5b for the total on Line 5.
The two sub-lines can carry different percentages. Some contracts apply the full rate to labor and installed work but a lower rate, or zero, to stored materials, since materials on a pallet are easier to verify than finished work. If the contract sets a single flat rate, both sub-lines use the same number. Column I on the G703 handles variable retainage by line item; leave it blank when the project uses a fixed rate across the board.
Line 6, Total Earned Less Retainage, equals Line 4 (total completed and stored to date) minus Line 5. Subtract amounts already paid on previous applications and you have the current payment due. Any error on 5a or 5b cascades through every line below it.
Handling a Midproject Rate Change
Many contracts reduce the retainage rate at a milestone, most often 50% completion. A common arrangement starts at 10% and drops to 5% after the halfway mark. Some contracts stop withholding entirely once cumulative retainage reaches a fixed dollar cap.
The transition draw is where mistakes cluster. Take a $500,000 contract carrying 10% retainage for the first half and 5% for the second. At the halfway point the owner is holding $25,000. On the next draw the contractor bills $50,000 of new work. Retainage on that $50,000 is now 5%, or $2,500, not the $5,000 it would have been at the old rate. Cumulative retainage after this draw is $27,500. Forgetting to update the percentage produces over-withholding, ties up cash, and creates reconciliation problems later.
Track the cumulative retainage balance on every pay application and compare it against the contract’s reduction trigger or dollar cap before you submit. The G702 itself does not flag when you have crossed a threshold, so a spreadsheet running alongside it is worth the effort.
Calculating Retainage on Subcontractor Invoices
A general contractor withholding from a subcontractor’s invoice uses the same formula. The rate should mirror what the owner is withholding from the GC. If the owner holds 5% from the GC but the GC holds 10% from the sub, the GC pockets the spread, and in a growing number of states that violates prompt-pay or retainage statutes.
Flow-down clauses keep the percentages aligned. A well-drafted subcontract ties the sub’s retainage rate to whatever rate appears in the prime contract, including midproject reductions. When the owner drops the GC’s rate from 10% to 5% at the halfway mark, the GC passes the reduction through to every subcontractor. Reading the subcontract before signing is the practical fix for one of the most common payment disputes in construction.
Statutory Caps That Override the Contract Rate
Retainage percentages are not purely a matter of negotiation. Many states impose statutory caps, and any calculation that exceeds the cap is unenforceable regardless of what the contract says. Caps of 5% are common, particularly on public projects, though some states allow up to 10% during early phases and require a reduction to 5% after the project is half finished. A handful of states prohibit retainage entirely once substantial completion is reached.
These caps apply to both prime contracts and subcontracts. If the project sits in a state with a 5% statutory maximum, plugging a boilerplate 10% figure into the formula produces an illegally high withholding. Check the retainage and prompt-payment statutes in the project’s state before finalizing any pay application.
Federal construction contracts follow the Federal Acquisition Regulation, which caps retainage at 10% of each progress payment and treats it as an exception rather than a default. If the contracting officer determines the contractor is making satisfactory progress, the regulation directs payment in full with no retainage. Retainage is withheld only when progress is unsatisfactory, and the contracting officer can reduce the amount as performance improves or the project nears completion. For individual buildings or divisions of work priced separately, payment is made in full upon completion and acceptance of that portion, with no percentage retained.1Acquisition.GOV. 52.232-5 Payments Under Fixed-Price Construction Contracts
On federal projects, the prime contractor must release retainage to subcontractors within 30 days after the subcontractor’s work is satisfactorily completed. That timeline runs from the date the prime receives payment from the government, not from the date the sub submits an invoice.2eCFR. 49 CFR 26.29 – What Prompt Payment Mechanisms Must Recipients Have?
Calculating the Final Release
Once the project reaches substantial completion, the accumulated retainage becomes payable. The final request is typically submitted as a standalone retainage-only pay application: current-period work shows zero, and the full retainage balance appears as the amount due. The architect or owner representative certifies that all punch-list work is finished before approving the release.
Owners rarely release the entire balance the moment substantial completion is certified. A common approach is to release the bulk of the funds but hold back 150% of the estimated cost to complete remaining punch-list items. If the punch list is valued at $10,000, the owner might keep $15,000 and release the rest. Once the punch-list work is done and accepted, the remaining holdback is paid, so the final retainage billing may happen in two stages.
Most state prompt-payment statutes require the owner to release retainage within 30 to 60 days after the project is accepted. Missing that window can trigger statutory interest, and in some states the contractor can recover attorney’s fees on top of the unpaid balance.